﻿    <p>
      <u>Definition from IAI</u>: This function returns true if
      the different fill area styles are assigned correctly to
      the <i>IfcFillAreaStyle</i>. Only certain combinations of
      the entity types provided by the <i>IfcFillStyleSelect</i>
      are allowed.
    </p>
    <p>
      Return false:
    </p>
    <ul>
      <li>if more then one externally defined style is assigned
      </li>
      <li>if an externally defined style is given and any other
      internal style definition is attached additionally
      </li>
      <li>if more then one background colour is assigned
      </li>
      <li>if both, a hatching and a tiling is assigned
      </li>
    </ul>
    <p>
      otherwise return true
    </p>
    <blockquote>
      <font color="#0000FF"><small>HISTORY  New function
      in Release IFC2x3 TC1.</small></font>
    </blockquote>